The present invention generally pertains to audio signal processing and is particularly directed to improved audio signal scrambling and digital scrambling systems with pulse amplitude modulation (PAM) of the scrambled digital audio signal for transmission in the non-video information intervals of video signals.
There are several prior art systems for scrambling and descrambling audio signals, including systems wherein an analog audio digital signal is converted to digital signal samples, and the bits of the samples are exclusive-OR'd with the bits of a unique keystream to scramble the signal.
There also are several prior art systems for pulse amplitude modulating of digital audio signals.